More recent communication architectures provide for call-processing networks to be separated into connection-service-related units and the transport of useful information (bearer control). This results in separation of connection setup and bearer setup. For communication traffic, such a concept means that there is no longer a strong tie to the network topology. In addition, network consolidation, that is to say the replacement of smaller and possibly outmoded switching centers with conventional concentrators and access networks or with access gateways connected on a packet basis, results in the need to control a large subscriber and connecting-line peripheral area using a single switching node. This means that demands for ever larger switching centers/call servers are becoming increasingly significant. Examples of these are demands for one million subscribers to be able to be served by a single conventional switching center or by an IP-based call feature server.
However, the switching centers, call servers or media gateway controllers which exist at present are designed for a particular maximum peripheral area. This is determined, inter alia, by the command masks of the machine language, the data stores of central and peripheral devices, the performance of these subsystems and the capacity of the intercommunication between these units. In addition, the expansion stages for these switching centers are operated significantly below the maximum expansion from the viewpoint of cost, since this is the only way of ensuring optimized costs. (The lowest costs are meant to be where the most frequent expansion size, on average, is located). This allows the system boundaries to be increased generally only by providing considerable development expense. This aspect is also intensified by the high level of complexity of the switching systems, which is caused, inter alia, by the fact that a large number of call-processing features are provided at the same time as almost total failsafety and maximum system availability. From the point of view of limited development budgets and rapid product availability, alternative solutions are therefore becoming more significant.
In the prior art, the peripheral area is subdivided and tied to various switching nodes, which are themselves meshed among one another or via interposed further switching nodes. This has the associated drawback that the network structure is artificial and requires high levels of administration expense. In addition, in the case of #7 signaling, unwanted additional point codes for the internal addressing are required which need to be taken into account in the external remote systems. Finally, from the point of view of the user, not just one switching center needs to be operated/administered but rather a plurality of switching centers in a given network.